Erectile dysfunction (ED) is an extremely common sexual dysfunction characterized by the inability to develop or maintain an adequate erection of the penis during sexual performance, or during rapid eye movement (REM) stage sleep. It may be primarily vasogenic (aka organic, when REM stage sleep related adequate erections do not occur), psychogenic (when REM stage sleep related adequate erections do occur), or mixed vasogenic and psychogenic in origin.
A penile erection is ultimately the outcome of the hydraulic effect of blood entering and being retained in the inflated erectile sponge-like bodies within the penis. The physiology of normal erectile function and pathophysiology of ED are highly complex and multifactoral in nature, involving amongst other determinants, local tissue factors, autonomic nervous system regulation, endocrine factors and higher mental function, the complex interactions of which are not yet fully elucidated, and are the subjects of continuously ongoing study. While a comprehensive review of this subject is beyond the scope of this description, the essential clinical condition of ED is indicated when a satisfactory erection is consistently difficult to produce and maintain.
There are various possible causes and co-morbidities associated with ED, however the major cause of vasculogenic ED is related to clinical or sub-clinical atherosclerotic, and degenerative conditions of the vasculature of the penis, and or loss of elasticity of the penile spongy tissues, which are considered mostly responsible for generating organic erectile dysfunction These degenerative conditions are widely considered to be causally related, at least in part, to a state of endothelial dysfunction.
Currently, treatment of erectile dysfunction is limited to on demand solutions which usually consist of drug therapy, or the use of a variety of physical approaches, all of which are giving a limited time solution to help in achieving intercourse within a short period of time i.e., between 30 min to few hours. There is no reasonable treatment for the chronic condition.
Drug treatment is most often based on the use of the phosphodiesterase type 5 (PDE5), inhibitors (the first of which was sildenafil or Viagra), a class of drugs known to improve erectile function. These drugs also improve endothelium-dependent vasodilation through increased NO production. Less commonly, treatment can involve prostaglandin tablets in the urethra, injections into the penis, a penile prosthesis, a penile pump or vascular reconstructive surgery.
Often such pharmacological methods fail, or are contra-indicated in many men, including those diagnosed with heart conditions, hypertension, glaucoma and many other conditions, and may also carry increased risk of strokes, particularly in those suffering from arrhythmias, or those having suffered a previous heart attack or stroke, difficulty breathing, vision problems, headaches and flushing. Furthermore they often cause side effects such as headaches, gastrointestinal upsets, diarrhea, blurred vision, urinary tract infections, or pathologically excessively long-term erections (priapism), amongst others.
Physically based treatment methods most typically involve the use of a purpose-designed external vacuum pump to attain erection and maintain it to approximately 30 min, with a separate compression ring fitted to the penis to maintain it. Such device helps draw blood into the penis by applying constant negative pressure. This type of device is sometimes referred to as penis pump and is used just prior to sexual intercourse. Several types of vacuum therapy devices are available with a doctor's prescription.
These pumps should be distinguished from other penis pumps (supplied without compression rings) which, rather than being used for temporary treatment of impotence, are claimed to increase penis length if used frequently, or vibrate as an aid to masturbation. More drastically, inflatable or rigid penile implants may be fitted surgically.
The commercially available pumps to treat erectile dysfunction have several disadvantages: They require 10 to 30 minutes to achieve and maintain an erection. The constriction ring needs to be very tight on many men in order to maintain the erection, and this can be painful. In addition, the erection men achieve using a vacuum pump is less aesthetically pleasing than one that occurs using other methods. This is because the blood that is drawn into the penis when using the vacuum is mostly from the veins and has low levels of oxygen, which makes the penis bluish or gray rather than pink. The erection is also cooler in temperature than one that is obtained “normally,” because the blood in the penis is mainly from the veins, not the arteries, which is warmer.
Several mechanical devices have been used in erectile dysfunction; U.S. Pat. No. 5,501,650, “Automated masturbatory device”, describes a device that generates back and forth strokes to the penis caused by positive and negative applied pressures within the system when applied to the heavily lubricated penis, causing displacements of the penis relative to the apparatus, for the purpose of sexual stimulation. The timing of the cyclic pressure swings is predetermined and unrelated to the cardiac or vascular pulsatile cycle.
U.S. Pat. No. 4,407,275, “Artificial erection device”, describes a semi-rigid annular ring having individual expandable chambers on the internal wall that are distended separately by fluid pressure. A multi-port flexible conduit connected to the ring has individual ports for each chamber. Fluid pressure is supplied through the conduit manually by a bulb or electrically by a pump through a circular valve plate allowing the chambers to expand and contract in linear sequence. When a penis is placed into the ring and fluid pressure is applied, blood is forced to the end of the organ through the successive expansion and contraction of the bellows due to positive and negative pressures supplied to the apparatus in wave fashion mechanically creating an erect condition of the organ.
However, in the device described in U.S. Pat. No. 4,407,275 the timing of the cyclic pressure swings is unrelated to the cardiac cycle, and the method is not intended to improve endothelial condition of the penile arteries.
It is an objective of the present invention to provide an externally applied non-invasive system for inducing vascular caliber changes in the blood vessels of the penis, and tissue volume changes of the sponge like erectile tissues unique to the penis (principally the corpora cavernosa and corpus spongiosum), to improve endothelial function of the penile blood vessels and to improve the elasticity of the sponge like erectile tissues of the penis, and thereby to improve erectile dysfunction.